Wheel aligning device



.July 15, 1941. A. P. PETERS 2,249,226 I WHEEL ALIGNING DEEVICE OriginalFiled June 10, 1939 4 Sheets-Shee t 1" Y J m E /4 7 ALBERT P ETEPJ July5, 1941 A P. PETERS 2,2 ,2 6

WHEEL ALIGNING DEVICE Original Filed June 10, 1939 4 Shee ts- She et 2fig. 5, 46

Z M I 26 ALBERT Pirzw A. P. PETERS WHEEL ALIGNING DEVICE July 15, 1941-.

Original Filed June 10, 1939 4 Sheets-Sheet 3 July 15, 1941*.

A. P. PETERS WHEEL ALIGNING DEVICE 4 sheets-sheet 4 Original Filed June10, 1939 ALBA-2r ,0 1 1675195 Patented July 15, 1941 T; OFFICE WHEELDEVICE Sa'n Francisco, Calif.

Albert 1'. Pete",

Original application J 278.507. Divided 1941, Serial No.

2 Claims.

This invention relates to an aligning method and device. The presentapplication is a division of my United States application Serial No.278,507, filed June 10, 1939, and entitled ing method and device."

An object of this parts of a vehicle,

supports can be the assembly and Another object such-as the wheels andwheel determined constantly during adjusting operations. of this.invention is to provide cause of any deviation from normal alignment ofsaid parts.

Another A further object of indicated by the relative position of lightrays or beams or the like.

A further object of this invention is to provide a device wherein lightrays are directed in a predetermined relative direction for indicatingrelative positions of machine parts, the direction accomplished byeasily detachable mountings, preferably by magnetic clamps to hold thelight directing elements in selected positions.

Particularly it is an object of this invention to provide a device forthe assembly of parts and mountings of a vehicle through level orrelative attitude indicators magnetically held in place.

A further particular feature of this invention is to provide anapparatus wherein all Kent and adjustment are accomplished by automaticconstantly visibleindication of relativeattitiide of the respectiveparts without requiring liismantling, repeated manual tests, andmeasurements of the relative position of parts: the indlcation beingaccomplished by the reflection of light rays onto a tabulated surfacefrom a definite position of the parts to be tested relatively to saidsurface so that an enlarged and sometimes exaggerated indication of therelative attitude of me 10, 1939, Serial ,No. and this 394,588

application May 22,

- said parts can be observed on the surface at all times while the workof assembly or aligning is continued uninterrupted; the surface being sograduated and arranged as to coact with the an aligning device that willbe ience in use and 20 influence a given attitude of the relative parts.Another object of this invention is to provide an aligning devicewhereby the degree and cause of misalignment of the wheels of a vehiclecan be determined speedily by the behavior of a light ray or light beamsrelatively to a graduated surface.

Other objects of this invention are to provide superior in point ofsimplicity, inexpensiveness of construction, positiveness of operation,facility and conven- Other objects variations of my of my invention. a

'With the foregoing and other objects in view, which will be mademanifest in the following description, reference is had to theaccompanying drawings for the illustrative embodiment of the invention,wherein: I

Figure 1 is a plan view of the arrangement of the. co-acting surfacesand devices with respect to an automobile for performing my aligningmethod. v

Figure 2 is a side view of the boards or surfaces with the automobile inplace ,therebetween.

Figure 31s a front view of a graduated surface showing the path of thelight ray travel thereon when the wheels tions. 7 V

Figure 4 is a side view of a wheel with my light direction device shownin section thereon.

Figure 5 is an end view of the wheel with the light directionalignerdevice thereon.

Figure 6 is an end view of a modified form of the device.

Figure '7 is an end device.

Figure 8 is a side view of a magnetically clamped aligning device.

are turned in opposite direc-' view of another form of my Figure 9 is anend view of the magnetically clamped aligning device.

' side of the vehicle.

Figure 13 is a perspective diagrammatic view of the device on a wheel inrelative position to the graduated surface so as to indicate thereoncamber.

Figure 14 is a front view of the graduated surface showing theindications for the toe-out" and turning radius.

Figure 15 is a plan view of the steering rod assembly the adjustmentorbending of which influence the toe-in," toe-out" radius.

Figure 16 is a front view of the graduated surface showing the lines oftravel of the light beam on the surface at various alignments of thecompound adjustment for caster and king pin inclination,

'Figure 17 is a sectional view showing the king pin inclinationindicated on the diagram in Figure 15.

Figure 18 is a side view of the steering-knuckle showing the axisposition causing the caster indicated on the diagram in Figure 15.

My method in general includes the steps of assembling the parts of amachine bythe use of a leveling indicator held magnetically ona desiredpart. At a certain stage of the assembling operation the aligningadjustments are made by means of a ray or beam of light projected upon agraduated screen from a predetermined position relatively to the screen.The relative attitude of said parts can be ascertained by observationfrom a distance and the parts can be adjusted until the indication onthe graduated screen corresponds to a desired alignment.

In detail my method includes the steps of preferably magneticallyattaching a light projecting element to a part of a machine, forinstance to the chassis of a vehicle or automobile, so as to point orproject the light beam to another part of the chassis where anotherpart, such as the axle must be assembled in direct line with said lightbeam. The assembly can be accurately performed at the point constantlylocated by the fixed beam of light. Then for relative alignment of partsof such assembly calibrated levels are magnetically located and drum. Bythe use of such calibrated levels the and turning steering gear isadjusted and the various adjustments such as the camber, caster, kingpin slant and the like are roughly set. Then final adjustments arechecked and achieved accurately by the projection of light beams fromsaid parts onto a graduated screen outside of the vehicle in such amannerthat any misalignment is exagge'rated for ready observation.

The first step is illustrated on wherein the chassis I of the each sidethereof supported alight projector 2 directed forwardly to the desiredlocation of the ends of the front axle 3. This step may be also used forstraightening the frame of the vehicle by Figure 10,

held on the brake automobile has on detecting the distortions of partsof the frame from straight aligned positions as indicated by the lightbeams.

- The second step is illustrated on Figure 11, wherein the levels 4 aremagnetically attached to a brake drum 5 so as to allow rough setting ofthe wheel and steering gear mounting during assembly.

The third step is illustrated on Figure 12, where, after the assemblyand rough setting of the wheels, the light projectors magnetically heldon the wheels project beams of light, preferably in the form of finepoint or hairline shape light rays into a spaced screen 6 and finaladjustments of the wheel and its mounting are made to correct errors ormisalignments indicated by the position or path of the light beams onthe graduated screen.

In the event of testing or aligning wheels the same can be accomplishedwithout dismantling or measurements on the floor. The automobile islocated on a graduated base or floor chart I so that its wheels are at adefinite distance from the screens 6, then alight beam is projected fromthe rear wheels to the front axle or wheels to check the alignment withthe front wheels. Then the light beams are projected from each of thefront wheels onto the screen 8 so that the paths of the light beams at acomplete turn of the wheels in either direction relatively to saidgraduated base I are projected on the graduations of the screenindicating the relative attitude of the wheels.

It is part of my method to so project the light rays or beams from thefront wheels that the camber of the wheel is truly shown relatively tovertical and horizontal markings, and so that the caster misalignment isevidenced by distortion horizontally and king pin misalignment bydistortion vertically with relation to corresponding horizontal andvertical coordinates of the graduations on the chart or screen 6, Thetoe-in? ftoe-ou and turning radius, are indicated by the balance of theincrease of distance at turns to both directions between the'llght beamsprojected from front wheels. By first charting the path of projectedlight beams on a screen 6 corresponding to normal alignments, deviationsfrom that charted path indicate misalignment, and according to thedirection and angle of deviation the cause of misalignment can bedetermined with certainty without dismounting the wheels or measuringthe wheel positions, wheel mountings or steering gear assembly. It ispref.- erable that the light beams be projected from magnetically heldsource easily and accurately maintained in position on the part to betested.

The apparatus for carrying out my method includes the graduated base orfloor chart I on which the automobile 8 is located on a predeterminedgraduation line corresponding to a given type of vehicle. Aligned withthe center line 9 of the graduations of the base I is the screen 0 whichhas a central panel H and sides or wings I! preferably hinged at l3 soas to be adjustable to desired angles. Fastening strips ll, or othersuitable latches, hold the wings ii in their adjusted angular positionsrelatively to the central panel H. The panel H and the wings I! areprovided with vertical and horizontal graduations l5 spaced at a givenspacing to permit readings corresponding to actual relative attitude ofthe wheels I of the automobile 8 located at a predetermined distancefrom the screen 0. There may be charts provided on the screen 8indicating the normal location or path of light projection for a giventype or model of vehicle with which the behavior of the correspondingtype or model of vehicle under test can be compared. Markings for normalpoints relative to which adjustments may be made-can be also pinned, orhanged on suitable hooks or the like on the charts or screens 6.

The projector 2, in the illustrative form herein described, includes atube II in one or both ends of which is an electric light socket l8suitably connected to a source of electricity. A suitable light globe isis in the light globe I8 is a reflector 20. In front of the light globeI9 is a shade 2| which has an opening for the the shade in the formshown in Figure 6 has socalled cross hair slots 22, and the shade shownin Figure 7 has spaced point apertures 22 to transmit light raysreflecting dots on the screen transmission of light rays in a selectedshape of beam or beams. For instance,

the socket l8. Around instances the existing bolts or bolt holes may beutilized for fastening the projector 2 in place. For instance theprojector tube may be supported on brackets the ends of which are heldby the usual bolts in the usual bolt holes of the brake drum. r

It is to be noted that the tube ll of the projector 2 has a pair ofbubble levels 4| located at right angles to each other whereby the useof levels in adjusting is combined with the light beam indications foraccuracy. This also facilitates the accurate location of the projector 2at a desired angle.

In operation, for-instance inconnection with vehicle wheels, the axles,knee action units, or independent wheel suspensions are tobe firstbolted or attached to the-frame. Inforder to insure a degree of accuracyof their alignment the beam of light is preferably magnetically held 6.In the extreme end of the tube I! are lenses 24 in a suitable casing 25so as to be adjustable for proper focusing of the projected light beams.Similar projection units are provided in both ends of the tube II asshown in Figure 4, projecting light beams in opposite directions.

The projector 2 is mounted on a bracket which has three clamps 26adapted to clamp over-the tire of the wheel It at two horizontallyopposite points and at a point at the top at right angles to thehorizontal clamps. Aligning plates 21 hold the bracket in a planesubstantially parallel with the plane of the wheel It.

For quick and accurate adjustment it is preferable that the projector 2be magnetically clampedand held in place as shown in Figures 8 and 9.netic clamping of the projector 2 permanent magnets 28, each of bularhub 29, fitting over the tube l1, and legs 30 spread at an angle buthaving ends 3| leveled substantially parallel with the axis of the tube11. In this manner when the magnetic clamps are engaged with a surfaceof the part to be tested the projector 2 is automatically aligned withthe surface so engaged. Inasmuch as the legs 30 are of such length thatall the ends it thereof are aligned with eachother the projector is heldparallel with the surface engaged by its magnetic clamps. In someinstances, such as for certain indications of so called toe-inadjustment, magnetic spacer washers 22, as shown in Figure 8 may beinterposed between the ends SI of the legs 30 near one end of theprojector 2, and correspondingly narrower washers 33 placed below theends 3| of the legs 30 of the middle clamp 28 so as to hold theprojector 2 at a predetermined outwardly diverging angle relatively tothe surface of the wheel l6 so that projected from the projecwheels i801' the vehicle are parallel then the wheels l6 are actually adjusted toa degree of toe-in ness of said spacer washers 32 and 33. The magneticclamps 28 are held in adjusted position on the tube IT. by means ofsuitable setscrews 34 so that all the magnets 28 point with their legs30 toward the surface to be tested. The direction of the legs 38 may bereversed by placing the end magnets 28 on the tube I! so that the legs30 converge toward the middle of the projector 2. Thus the same. clamps28 may be used to clamp on larger or smaller surfaces.

While the magnetic clamping and adjusting of the projector 2 is alwayspreferable, yet in some are shown three which has a tution of. the wheelassembly aligned on each side of the frame I.

on each side of the frame I. The opposite light beams are placed somedistance back of the locaand are equally The beam of light is thus fixedin this illustration by the symmetrical mounting of the projectors 2 onthe opposite sides of the frame I 'as shown in Figure 10 so that thelight beams point to the desired location'of the units to bemounted atthe front end of the frame. The axles, knee action In the illustrativeembodiment of magunits, or independent wheel suspension are in properlyaligned position relatively to the frame I when the light beamsprojected from the pro- Jectors 2 point directly upon said mountedunits. On the usual front wheel i 6 of the automobile 8 the wheelspindles, hubs and brake drums are .then attached. In the adjusting ofthese parts to a proper caster, camber and king pin slant the levels areused on suitable platforms or brackets attached to the parts worked onpreferably by magnetic clamps. Thus these approximate adjustments areachieved before the wheel is attached in place.

After the wheel I 6 is assembled the final alignment is accomplished bysetting the wheels II at a predetermined distance from the graduatedscreen or chart 6, and attaching to the wheels It the projectors 2 sothat a light beam is projected from each wheel it upon the screen orchart 6. By manipulating the wheels H5 in the remeasure the variousunits workedpn'.

determined by the thickbeam of light on the screen or chart 6 changesthe camber, toe-in, caster,

manner of their actual operation the location and path of the lightbeams on the graduated chart] gives accurate indication and reading ofthe rise andfall of the wheels, the steering angle, the king pin slant,the included angle, turning radius or other behavior'of the wheels itwhen they are turned in either direction. This is accomplished by thesetting of the wheels on a predetermined line on the base or floor chart1, which renders the readings on the wall chart or screen 6 accurate.The mechanic does not need to check instruments or The location as themechanic is making the adjustments and indicates the setting.

An example of necessary adjustment is the camber of the wheels. Thefront wheels of a vehicle are closer together at the bottom or groundthan they are at the highest points directly above. The idea ofcambering is to make the center line of the usual spindle bolt or itsequivalent, coincide, as near as practical, with the center of contactof the tire with the ground. In other words, the purpose of the camberis to 5 bring the point of contact of the tires with the road morenearly under the spindle pins, or king bolts, thus permitting the car tosteer more easily. This camber is usually given to the steering knucklesand spindle by tiltin, the steering knuckle so that the steering knuckleis at outwardly and upwardly spread angle instead of beingperfectlyvertical. In Figure 13 the vertical line of the cross-hair line isparallel with the wheel IS. The cross like beam 48 appears at an angleto the vertical graduations on the screen 6. If the'camber is lost or isnot of proper angle, then the mechanic can adjust the axle, or the kneeaction support, or the like mounting, until the vertical line of thecross beam on the screen 6 is at a desired angle or camber.

Another example of adjustment of the front.

wheels is the so-called toe-in which is an adjustof the cross steeringrod or tie rod 49 from one steering knuckle. to the other. If this doesnot correct the adjustment then it may be necessary ment to onset thewearing action on the tires by the camber, and to produce more even wearon them. This refers to the converging of the front wheels toward eachother at the front. An additional reason for this adjustment is thatwhen the vehicle is running at high speeds, the wheels have a tendencyto toe-in. If toed-in too much, or not enough, the treads of the tireswill grind. The toe-in is checked in my method and device for attachingto the front wheels I 6 the projectors 2 so as to reflect a light beamonto the screen or chart l5. Then the spacers 32 and 33 are placed underthe legs of the magnets 18 as heretofore described so as to diverge thelight beams relatively to the plan of the wheels it to the desired angleof toe-in. By adjusting the wheels until the light beams are parallelthe desired toe-in is set.

The so-called toe-out and theturning radius of the front wheels l6 areclosely related to the toe-in adjustment of the wheels. As shown inFigure 14, these adjustments can be easily checked by the varyingdistance between the re- 'flections of the light beams on the chart orFigure 14. At the extreme turn the distance the projected beams isdenoted on Figure 14 by r the letter A. Then the wheels (6 are turnedfully in one direction, for instance, toward L in to straighten abending of the axle 3 or of the spindles. The most common cause ofdiscrepancy in the adjustment of the toe-out or turning radius is thatone of the steering arms 5| is bent. Therefore this discrepancy can becorrected by straightening the steering arm 5i until the relativedistance between the light beam points R and L is of the desiredbalanced length.

Another common and important adjustment is the adjustment of the casterof the front wheels. This adjustment is an upward and rearward inclineof the steering knuckle 52, as shown in Figure 18, so that the steeringaxis 53 therethrough' meets the ground in advance of the point ofcontact of the wheel. The vertical axis 54 in Figure 18 pointssubstantially toward the point of contact of the wheel at the bottom.Thus the front wheels ii are purposely placed out of perpendicular, orcastered, in order to bring the point of contact between the tire androad more directly under thesteering spindle 55.

Due to this offset from the perpendicular the wheels I6 rise and fallasthey are turned in the respective directions. Another adjustment whichmanifests itself in the rise and fall of the wheels while being turnedis the inclination of the king pin 56 as shown in Figure 17. Thissocalled king pin slant is sidewise and inward of the vehicle at the topof the king pin 56, to facilitate steering. The rise and fall of thewheels I6 is therefore the result of a compound action oradjustment ofthe caster of the steering knuckle and of the inclination or slant ofthe king pin 56. The wheels in this respect mustbe balanced.

The path of thelight beam reflection on the screen 6 indicates anyirregularity of the rise and fall of the wheels l6 during a turn and thepath responds differently to irregularities caused by one or another ofthe component causes of said rise and fall, For instance, viewing Figwe16, the middle path 51 is the normal path when the caster and the kingpin slant both are normal. This path 51 may be indicated on the chart inany suitable manner such as by pinning or hanging or drawing on thechart the normal light beam path 51 for a certain type of vehicle frontwheels. The offset of the king pin manifests itself in variation of thepath of light along the vertical coordinates of the chart. Thehorizontal components of the paths of light inbetween Rand L is asdenoted by the letter 11 dicat ethe relative caster alignment. When thewhich by reason of the compensating turning radius is larger than thedistance A. Then the wheels are turned in the other direction and at theend of the full turn the distance between the points L and R is asdenoted by the letter C which is also usually largerthanthe initialdistanceA.

Any difference between the distance 3 and king pin inclination isincreased above the normal angle of inclination then the path isdistor-ted upwardly from the normal as shown by the paths 58 on Figure16. A straightening of the king pin position relatively to the verticaland outwardly causes a distortion of the light a beam paths downwardlyas shown on the paths ,58 below the normal paths 51. On the other hand,it was found that the horizontal distortion of said paths 58 and 59corresponds to a I misalignment of the angle of caster. It is importantthat the caster and king pin inclination of the front wheels beequalized, and this characteristic is quickly ascertained and correctedby observing the relative paths of 'the lightbeams projected onto thescreen. The mechanic can change the adjustments, or tilt the axle, orbend the knuckle, while observing the light toe-in is usually adjustedby adL1ustingthe length beam on the chart until the light beams indifcertain adjustments.

cate equalizationand correction ot'the adjustments on bothiront wheels16.

It is to be noted that there is a certain amount travel of thewheels itduring turning even when the vehicle is otherwise stationary and thistravel would cause iurther distortion of the which might be misleadingin :some instances. It is therefore desirable that during the checkingvoi any adjustments that require f ious types of vehicles and thevehicles can be quickly tested relatively to such chart. The

characteristic deviations from 'such normal chart definitely determineand indicate the mantling the' wheels, -the steering gear, or mountings.By coaction with the floor chart I eachtype of vehicle can be accuratelylinedup turning of the. wheels, the front wheels be either at apredetermined distance fromthe wall chart oi! the ground or be supportedon suitable'swivei plates, so that only the true rise and tall caused bythe wheel mountings is indicated on the screen or chart., ,p v

The alignment or the rear wheels with the jectinglight iromthe' rearwheelsto the front wheelsfinrzalignment with the projectors '2 .ontheiro'nt 'fwheels. When the light beams coincide" then the rear wheelsare properly aligned with the i'ront wheels. The mechanic can make hisadjustments in 'caseoi misalign ment until thelight beams from the rearwheels the light beams from the front wheels.

.The wings I2 01 the screen 8 are preferably always set so that they aresubstantially at right" angles to the beams of light when'the wheels arein extremely urned positions. The charts I I on the screens' 'eseregraduated and'marked to indicate the true distance or distortionrelatively to a set' point or line on the floor chart I. If so desired,therear wheels may be checked by rearward projection of light beams on arear screen 6 as shown in Figure 1. Screens or arebroughtinto'directionalcoincidence with charts may be employed in otherrelati've positions, such as at one side or both sides of the vehicles.In such arrangements the graduationsmustbe tabulated to allow forlateral reading of variation of light paths corresponding to- Thecharacteristics of wheel .location and movements responsive to certainadjustments are thus reproduced on an enlarged scale in readilyobservable position. The instruments are quickly and easily attachableto the parts toor :vertical screen 6. The indication by the lightbeamsremains constantly observable while the -mechanic makes theadjustments obviating the need in repeated stopping of the work for I.15 measurements and checks. The diagnosis and irontwheeisisalsotreadily ascertained by Droadjustments of the parts and wheels arethus obtained with accuracy and ease, and with immediate indication andcorrection of the cause 5 otherwisethan necessitated by thescope oi theappended claims.

I claim as my invention:

1. An apparatus for depicting the deviation from predetermined standardturning characteristics of theturning' characteristics of the frontwheel or a vehicle including means for projecting a beam 01' light fromsaid wheel in fixed reiation'to the plane thereof and a screen havingindicia thereon which coincide with the Dattem formed on said screenwhen and only when said screen intercepts said beam oi light at apredetermined distance from said wheel and said wheel'has saidpredetermined standard turning characteristics.

,2. An apparatus for depicting the deviation from a predeterminedstandard angular inclination' 01 the front wheel of avehicle as mountedon a king pin, said apparatus comprising means for projecting a beam oflight, means i'or attaching said projecting means to said wheel in fixedrelation to the plane thereof, and a screen having indicia thereon whichwill coincide with the pattern formed on said screen by said beam when,and only when, said screen intercepts said beam at a predetermineddistance from saidwheel and said wheel has said predetermined standardinclination. a

ALBERT P; PETERS.

